Dear Lifehacker, I know about tipping the obvious people—cabbies, waitresses/waiters, barbers, and so on—but there are many times when I'm not sure if I'm supposed to tip other service people, like the cable guy, food counter person, or electrician. Can you help me figure out what's customary?

Signed, Troubled by Tipping

Dear Troubled, Tipping really is one of the most confusing customs—one that's had a long and sordid history in the US and is often the subject of heated debates. That's because there are no real "rules" for tipping, and the etiquette of it can seem pretty arbitrary. Besides varying opinions for who and how much to tip, customs vary by country as well. Ask a dozen people when and how much they tip, and you'll get a dozen different answers.

Food-Related People

Food Pickup/Counter Person: The Emily Post Institute says those jars at the coffeeshop or take-out counter don't require tipping because it's not a high level of service, although you can tip a little bit if you're a regular customer or the server does something extra for you. Tipping.org recommends a small tip of 50 cents to $2 for orders under $30; 5-10% for $30 to $60 orders (especially if packaging the order is difficult) and/or if the person helps take your order to your car. For large orders, which require more condiments, plates, etc., 8-10% is recommended. Photo by Marcin Wichary

Picking up from a restaurant: The above suggestions work for most food counters where you see tip jars, but an exception is when you order from a diner or restaurant for pickup. In that case, the recommended tip is 10%, according to Tipthepizzaguy, which says that waiters prepare that food and are taxed on carry-out sales. (But, yes, tips are not expected at pizza places.)

Buffet: Tip 5-10% of the total bill. Tipping.org says this may depend on how much work the waitstaff does (e.g., if they don't do much besides bring utensils versus taking orders and bringing drinks)

Delivery person: Most of us know to tip food delivery people, who often use their own cars; however, do you tip a dollar amount or a percentage? Tipthepizzaguy recommends 15%, with a $3 minimum and adding an extra $1 if he had to travel more than three miles. On the other hand, Daily Finance says food delivery tips as a percent of the total bill doesn't make much sense, because there's not as much customer service, so $3 to $10 is their recommendation.

Supermarket bagger: This was the most confusing category I found. Most responses on forums around the web say that people don't tip supermarket baggers and in many cases baggers aren't allowed to accept tips. However, Tipping.org recommends tipping $1 per bag. As with other tipping advice, the "above and beyond" rule might apply here: Consider tipping if the person brings your bags out to the car or does something extra.

Home-Related Services

Building supervisor: Opinions also vary greatly on this. You might want to tip when the super does some work on your apartment, but then again, it might depend on where you live. If you're not sure, a holiday tip of $50 to $100 may make the most sense, according to this MetaFilter thread (LearnVest recommends $20 to $80 or a gift).

The cable guy: No need to tip, though an offer of a drink is nice. However, some cable and satellite installers on AnandTech forums say they've received and appreciated tips, so if the person goes above and beyond (suddenly you have free movie channels?) go ahead. Photo by rick

Home service providers (e.g., electrician, painters, lawn service): No need to tip. The consensus on an Apartment Therapy post is that because these are professionals rather than service people, tips aren't warranted. However, for some arbitrary reason, painters do get tipped, according to Angie's List in a Seattle Time's article.

Exterminator: Because this can vary by area, call the company before you get service done to ask what's normal.

Furniture/appliance delivery person: $5-10 per person or more if what's being delivered is especially heavy or difficult to maneuver.

Flower delivery person: $2 to $5 or up to $10 if the plant is heavy or large.

Car-Related Services

Gas station fill-up person: No tip needed. If you want to tip the person for doing something extra (e.g., cleaning glass or checking fluids), $1 to $5 is fine.

Mechanic: No tip needed. This might depend on your relationship with your mechanic. If you want to tip because your mechanic does a great job, Tipping.org suggests $10 to $20 for jobs up to $500 or $50 for those above $500. Photo by Marcin Monko

Tow truck: $5 to $10 if they help you when you're locked out, $3 to $5 for a jump start/tire change; $5 or more for a tow.

Travel-Related Services

Concierge: $5 to $20, according to The National Concierge Association. You don't need to tip just for a simple restaurant recommendation, but if the concierge gets you tickets to a sold-out show, you should be more generous. Photo by Alan Light

Hotel maids: $2 to $5 a night is generally recommended, but CNN notes a study by Cornell University School of Hotel Administration that says only about 30% of hotel guests actually leave tips for the hotel housekeepers. The article notes that this position isn't really a tips-based one, unlike bellhops who usually fill out tip reporting forms for the IRS.

Bellhop or airport skycap: $1 a bag or more if it's heavy. The Bellman Gripes Page recommends $5 is the minimum tip for bellstaff.

Rental car shuttle driver: $1 per bag or more if they help with your luggage

Camp counselors: Depends on the camp. Some camps don't let their counselors take tips, while others will send parents a letter with recommended tip amounts (e.g., $1 a day). When in doubt, call the camp to find out.

Children's party entertainers: $15-25 depending on the performance

Dog walker:Dogwalker.com recommends giving a holiday tip at the end of the year, between 10 to 20% of the daily fee or a week's pay.

Tattoo artist: No tip needed. But if you want to: $10 to $15 for a $150 tattoo or $20 to $50 for more expensive tattoos is recommended.

Holiday Tipping

Because the end of the year is a time to show your appreciation for the people who've helped you all year long, many people give holiday tips. Here's a holiday tipping guide from LearnVest we've featured previously:

End-of-year tipping for the service people who help us out throughout the year is upon us. The…
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General Tipping Guidelines

If you are in doubt about whether or how much to tip, ask in advance. The Emily Post Institute says, for example:

If a department store is scheduled to deliver a new sofa, call and ask someone in the furniture department whether tipping is customary; in a hair salon, ask the receptionist. In some situations, leaving a tip could be seen as demeaning. Taking the time to find out what's expected can spare you an embarrassing moment.

If you're still in doubt and want to tip, you can't go wrong with 15%-20%. This depends on how good the service was.

Tipping is about expressing gratitude. The above recommendations are just that—recommendations. You should follow your gut and base your decision on whether to tip or not based on how regularly you see the person, how much they help you out, and perhaps how much their job or livelihood depends on your tip.

Hopefully the above tip examples will ease your mind the next time a possible tipping situation comes up.

Etiquette is, by its very nature, subjective. What's acceptable today probably wasn't acceptable 20 years ago, and what's unheard of right now might be commonplace in a decade. It might also be seen as pedantic to some, because if you boil it down, it's just an arbitrary set of rules that we all abide by to make all our lives easier. So weigh in and tell us what you think about this subject. It's one of the few times that just about everybody's opinion is more or less as valid as everybody else's. Got something you're curious about? email tips+etiquette@lifehacker.com